Cartesian coordinate system, also called Cartesian coordinate system, uniquely specifies each point on the plane through a pair of numerical coordinates. The coordinate system is the signed distance between the points of two fixed vertically oriented lines measured in the same length unit. Each reference line is called a coordinate axis or the axis of a system, and the point where they intersect is usually an ordered pair (0,0). Coordinates can also be defined as vertical projection positions from a point to two axes, expressed as signed distances from the origin.
Two number axes intersecting at the origin form a plane rectangular coordinate system. If the units of measurement on the two axes are equal, this rectangular coordinate system is called Cartesian coordinate system. A Cartesian coordinate system with two vertical axes is called Cartesian Cartesian coordinate system, otherwise it is called Cartesian oblique coordinate system.
The two-dimensional rectangular coordinate system consists of two mutually perpendicular number axes, and their zeros coincide. In the plane, the coordinates of any point are set according to the coordinates of the corresponding point on the number axis. In a plane, the correspondence between any point and coordinates is similar to the correspondence between points and coordinates on the number axis.